If a mid-size luxury SUV is in your fall wardrobe, the 2012 Mercedes-Benz ML350 may be the cable-knit sweater.

Its hardy construction is conservatively stylish, its practicality infused with elegance. This is a vehicle that is equally suited to shuttling five people to a rowing regatta or delivering them to opening night at the opera.

And if you've ever glanced at the price tag of a cable-knit sweater spun from cashmere or angora, you know there's always a way to spend entirely too much on something that is, after all, just a sweater.

Mercedes' refreshed and retuned sport-utility vehicle is now in its third generation and starts at $49,865 for the base model with a V-6 engine. An additional $1,500 will get you the more fuel-efficient V-6 diesel BlueTec that I tested. As was the case with previous MLs, all new models are built in Mercedes' Tuscaloosa, Ala., plant.

The base prices for each of the MLs are not unreasonable for the segment, which includes the Land Rover LR4, Acura MDX and BMW X5.

Unfortunately, a navigation system isn't standard; it's part of a $3,600 option package that also comes with a backup camera. And that's just the beginning. A leather package replaces the fake stuff with the real, bovine-donated kind. The handling package gives you 20-inch wheels and an adaptive air suspension.

Another package throws in adaptive cruise control that monitors the car in front of you, as well as blind-spot monitoring and lane-keeping assist. A rear entertainment system, a moon roof, a self-parking feature — all are offered if you're willing to part with serious money.

Finally, who can forget the $1,780 night vision option in which about 500 feet of the road ahead will show up on the navigation screen in an infrared display?

The final bill? The ML350 BlueTec I tested had everything you see here for $75,665.

That's an expensive sweater.

But stick to the basics, avoid all those add-ons (but spring for the navigation package), and you're rewarded with straightforward, prudent luxury.

The best part of this is the interior. Mercedes installed the same dashboard layout it is putting in many of its 2012 models. The color display or navigation screen now sits atop the center console and holds court over revised switchgear and brushed metal trim. A healthy portion of wood trim is also included in the mix.

As with the previous ML, Mercedes took a page from your uncle's outdated Buick and mounted the shifter on the steering column. This frees up more space in the center console for storage and gives the area a cleaner look.

The ML seats five comfortably; drivers with more passengers than cargo will have to wait until the 2013 model year, when Mercedes will offer it with seven seats. For now, the cargo space is average for this segment, though the rear seats fold completely flat if needed.

Changes to the exterior are minor, but welcome. The ML is more streamlined than before and components such as the grille and headlights mesh with one another much better, giving the vehicle a more complete, stylish look.

The ML350 BlueTec features a 3.0-liter, turbocharged V-6 diesel motor that makes 240 horsepower and a staunch 455 pound-feet of torque.

I also logged some seat time in the gas version, whose engine pulls 302 horsepower and 273 pound-feet of torque from a 3.5-liter V-6.

Despite the diesel's significant torque advantage, its acceleration doesn't pull back your jowls with force. Driving away from a stop is surprisingly subdued compared with the gas version. It also doesn't give you a towing advantage. Mercedes says both versions of the ML will do zero to 60 in 7.3 seconds and will tow 7,200 pounds.

During daily driving, both power plants are quiet yet assertive. Unless you really honkon the gas pedal, the engines don't make their presence known. The only transmission on either ML is a seven-speed automatic with paddle shifters, and both feature permanent all-wheel-drive.

Both models also had the aforementioned handling package. The system certainly works well, with the air suspension keeping the body balanced through turns no matter what their radius or your enthusiasm for them.

But nothing about the experience said it was worth the $5,150 that the package costs. I have a sense that an ML350 without this option will still go around a corner without being sucked into a wormhole or turning into a pumpkin.

All told, there was almost no discernible difference between the gas-powered ML350 and the ML350 BlueTec. The only thing that revealed its diesel powertrain was an idle not that different from your kid's school bus.

But to me, a little idle chatter is worth the advantage at the fuel pump. The diesel ML350 is rated at 20 miles per gallon in the city and 27 on the highway, while the gas ML350 is rated at 17 mpg in the city and 22 on the highway. In my time with each, I averaged 21 mpg with the diesel and 16.3 with the gas.

This difference in efficiency means it would take about 30,000 miles of driving the diesel to offset the extra $1,500 it costs at the dealership and the additional 10 cents a gallon you may pay currently for diesel fuel over premium-grade gasoline, according to the national average.

Anything beyond that 30,000-mile point would save you about 5 cents a mile, assuming the price difference between premium gas and diesel fuel stays the same. That's an additional $1,000 in savings by the time you reach the end of the ML's 50,000-mile warranty.

Yes, it's possible that if you're spending almost $76,000 on a mid-size SUV, you don't care about saving a grand in fuel costs.